Method of and means for rolling seamless tubing



FOR ROLLING SEAMLESS TUBING P. A. FOREN May 17, 1932.

METHOD OF AND MEANS Filed April 16, 1928 A TTORNE Y.

May 17, 1932.

Filed April 16, 1928 2 Sheets-Sheet 2 4 VINVENIOR. 44;?

A TTORNE Y.

Patented May 17, 1932 um'rsn STATES PATENT OFFICE.

3m n A.- FOREN, or MILWAUKEE, WISCONSIN, Assrenon T9 GLOBE STEEL moans 00.,

- on nInwAU EE, WISCONSIN, A CORPORATION 01 DELAWARE METHOD OF AND MEANS FOR ROLLING SEAMIQESS TUBING Application filed April 16,

This invention relates to the art of rolling seamless tubing.

Commercial rolling mill methods heretofore practiced in the'production of seamless tubing have usually included the following steps. v The heated billet, asit comes from the furnace, is first passed through a piercing mill in which it is transformed from a solid blank of cylindrical form into a hollow cylinthe action of thefplug on the interior thereof is extremely severe leaving the internal.

through the sizing mill.

surface scratched, torn, and gouged. The v tlOIl, of a rolling nnll constructed in accordthe solid blank is then transferred to a reeling mill in which it is rotated axially at high speed and simultaneously slowly advanced over a stationary plug designed to iron out the irregularities produced by the plug of the rolling mill. Thereafter the blank is. transferred to a sizing mill wherein it is reduced to a finished tube of accurate size. Tubes of smaller size are ordinarily passed through a reducing mill after passing The time consumed in transferring the blank from mill to mill, in passing it back and forth through the rolling mill, and in advancing it slowly through the reeling mill is ordinarily so great as to require reheating of the blank before the process is completed.

An object of the present invention is the provision of an-improved process and means forthe continuous rolling of seamless tubing, as distinguished from the hereinabove mentioned rolling operation which necessitated passing the blank back and forth.- through the rolling mill. This I have accomplished by passing the pierced blank, with a bar therein, through a series of pairs of rolls which are ombined in a novel, man- 192'3. Serial No. 270,290.

ner and coact with the bar to reduce the wall of the blank to a desired uniform thickness and to smooth out the external and internal surfaces thereof. By this novel method the severe action of the plug upon the bla-nk is avoided, the reeling process is eliminated, and the tube is completed within such a short period of time that reheating of the blank is unnecessary.

'Other more'specific-objects and advantages will appear. from the following descriptionv of a process androlling mill embodying this invention. 7

In the drawings Figure l is a view in side elevation of a series of rolls arranged to carry out the-tube rolling process of the present invention.

, Figs. 2 to 7 are enlarged sectional views .taken substantially along the lines 2- 2,

3-3, 47-4, 5 5, respectively.

Fig. 8 is an end elevation, partly in secance with the present invention.

In carrying out my novel process billet, as it comes from the'furnace, is passed through the usual piercing mill by which it is converted into a hollow cylindrical blank 10 in awell known manner. A round bar 11, considerably longer than the blank, is then inserted into the blank and both are passed longitudinally between successive pairs of rolls arranged substantially as illustrated in Figure 1.

In the series ofrolls shown the rolls 12-12 of the first pair are rigidly supported for rotation in a vertical plane, the rolls 13- 13 of the second pair are rigidly supported for rotation in. a horizontal plane, the rolls 14-14 of the fourth pair are rigidly supported for rotation in a plane inclinedlat a forty-five degree angle, and the rolls 1 5-15 of the fifth pair are rigidly supported for rotation in a plane normal to the plane of rotation of rolls 14- 14. Each of these rolls is substantially tangential to its companion roll and to a common center line which is coincident with the pass line between the rolls of each pair. A peripheral groove '16 of rounded contour. provided in each of these rolls, cooperates with a corresponding groove in its companion roll to provide a blank confining passage of definite form therebetween.

From an inspection of Figures 2, 3, 5" and 6 it will be noted that the depth of each groove 16 is somewhat less than the widththereof, so that the blank 10, in. passing between the rolls of each pair, is somewhat flattened and is thus pressed forcibly against opposite sides of the bar 11. The bar is thus impressed into the wall of the blank to reduce the thickness thereof within thatlimited area of contact with the bar. It will also be noted that the central portion of the base of each groove 16 is substantially concentric with the surface of the bar 11 through an anglew (see Fig. 2), which is ordinarily somewhat greater than forty-five degrees, so that throughout this limited angle the reduced portion of the wall of the blank is of substantially uniform thickness. I

It will thus be understood that, as the blank 10 with the inserted bar 11, passes between the vertical rolls 12-12 of the first pair, the

blank is flattened vertically against the bar to thereby reduce the wall thickness along the top and bottom of the blank; Then as the blank and bar pass between the horizontal rolls 13-13, the blank is flattened horizontally against the sides of the bar to thereby similarly reduce the wall thickness along the opposite sides of the blank. At this stage of the process however thick portions or ribs a-a and 6-?) remain intermediate the reduced portions thus formed. Theseare re moved by passage of the blank and bar between the pairs of inclined rolls 1 1-14 and 15-15. Thus, as the blank and bar pass between rolls 14-14, the thick portionsa-a are pressed against the bar and thereby -reduced in the manner above described; and as the blank and bar pass between rolls 15-15, the thick portions 6-?) are similarly reduced.

Since, as above pointed out, each reduced portion is of uniform thickness throughout an angle greater than forty-five degrees, each uniformly reduced portion merges with the adjacent uniformly reduced portions, so that the wall thickness of the blank is uniform throughout when it leaves the rolls 15-15.

It will be noted that as the blank 10 issues from the rolls 12-12 itstraverse contour is symmetrical with respect to the pass plane of the rolls 13-13 or more specifically, that the major dimension thereof is substantially horizontal and thus lies within the central plane of rotation of the rolls 13-13.- But as it leaves the rolls 13-13 its contour is unsymmetrical with respect to the inclined pass plane of the rolls 14-4 1. In order to avoid an undesirable distortion of the blank that might result from passing the blank directly from rolls 13-13 to rolls 14-14, provision is made for reshaping the blank to render the transverse contour thereof symmetrical with respect to the pass plane of rolls 14-44 before admission thereto. Although this could be accomplished in various ways, as by the use of fixed forming or drawing dies, I prefer to interpose a pair of reshaping rolls between the rolls 13-13 and 14-14. The rolls shown at 17-17 in Figures 1 and 4 are for this purpose. They are rigidly supported for rotation in a plane slightly inclined from the horizontal and are provided with unsymmetrical peripheral grooves 18 which cooperate to so reform the contour of the blank as to transpose the major transverse dimension thereof into the inclined central plane of rotation of the rolls 1 1-1 1. Since the rolls 15-15 are disposed in a plane normal to the rolls 14-14, the contour of the blank, as it issues from the rolls 14-14,is symmetrical with respect to the rolls 15-15, so that it may be passed directly thereto.

As the blank 10 and bar 11 issue from the rolls 15-15 they are passed through one or more pairs of rolls 19 designed to give the blank a true circular contour and to thereby free the same from the bar. The single pair of rolls shown at 19in Figures 1 and 7 are rigidly supported for rotation in an inclined plane normal to the pass plane of the rolls 15-15, and each is provided with a semi-circular groove 20, which grooves cooperate to form a circular blank confining passage between the rolls. As the blank passes therethrough the contour thereof is changed from the flattened form of Figure 6 to the circular form of'Figure 7 and by this transformation the walls of the blank are'freed from the bar. From the foregoing it will of course be clear that in one passage through the series of rolls hereinabove described the crude blank received from the piercing mill is transformed into a tube of accurate size and wall thickness whose external surface has been smoothed out by the rolls and whose internal surface has been smoothed out by the bar. As will be obvious, greater total reduction may be obtained by one or several repetitions of the process, as by the addition to the mill of another or several series of pairs of rolls corresponding to and relatively arranged asthose shownin Figure 1 with the clearance between the rolls and the bar in each successive series reduced and the peripheral speed of the rolls correspondingly increased. Tubes of reduced sizes may of course be obtained by passing the tubes, as they are received from the end rolls of the mill whether or not repetition. of the process as aforementioned is resorted to, through the usual sizing or"reducin g mills hereinabove mentioned.

The several sets of rolls 12-12, 13-13. 11-1-1, and 15-15 are all power driven.

. Rolls 19-19are also preferably power driven while rolls 17-17 may or may not be driven, depending upon operatiu g conditions.

During passage of the blank and 'bar between the several rolls the material of the blank, displaced by the reduction in wall thickness, goes to increasethe length of the blank. In order to encourage this lengthening process each of the several pairs of rolls 13-13, 14-14, and 15-15 are driven at a slightly greater speed than the pair of rolls immediately preceding.

Since the wall thickness of the tube as it leaves the rolls 15-15 is dependent upon the distance between the bases of the several grooves 16 and the adjacent surfaces of the bar 11 this wall thickne'ss'may within practical limits be varied at will by the use of bars of various diameters, it being of course understood that in changing from one wall thickness to another, the relative speeds of the several rolls is varied in order to obtain corresponding changes in tube length.

A rolling mill designed to carry out the process hereinabove described is shown in end elevation in Figure 8. It is mounted upon an appro riate bed 21, shaped to receive a forward ase casting 22 and a rear base casting 23. Suitable means,such as ribs 21 formed on the bed and coacting with corresponding grooves inthe two base castings 22 and 23, insure an accurate positioning of each casting relative to the other. The forward casting 22 supportsthe vertical rolls 12-12 and the horizontal rolls 13-13 through means to be later described and the rear casting 23 supports the inclined rolls 14-14 and 15-15 in a similar manner. Casting 22 is provided with a horizontal top face 24, terminating in a guide shoulder 25, and with a vertical side face 26, terminating in a similar shoulder 27. The two faces are. of the same width and both extend from front to rear of the casting. The rear casting 23 is provided with similar faces 28 and 29 each inclined at forty-five degrees and normal to each other and each terminating in similar shoulders 30 and 31.

The vertical rolls 1,2-12 are journalled in appropriate bearing blocks 32, adjustably mounted within an uprightframe 33, rigidly supported by a bracket 34 which extends upwardly from the side of the base casting 22. In this instance the bracket 34 is provided with a base plate 35 seated upon and fixed to the side face 26 and against the 'ide shoulder 27 of the casting. The .bloc s 32 are fixed in any position of adjustment by nuts 36 engaged with the blocks and threaded upon screws 37 which are simultaneously rotated in either direction through gearing 38 and an appropriate hand wheel 39. Thus of the pass line therebetweem.

by rotating the hand wheel 39 both rolls may be simultaneously adjusted toward or from each other without disturbing theposition Since the frame 33 and inclosed parts are full described in my copending application, erial No. 279,445, filed May 21,- 1928, a further or more detailed description thereof at this time is deemed unnecessary. Therolls 12-12 are driven from a shaft '40 through the usual spindles 41 and appropriate gear set enclosed within a housing 42. The gear housing 42 in this instance is'provided with a base plate 42' seated upon and fixedto the top face 24 and against the guide shoulder 25 of the casting 22. s The horizontal rolls 13-13 are mounted in a frame 43 substantially identical withthe frame '33 except that it is horizontally disposed. Frame 43 is supported ,by a bracket 44, substantially identical with bracket 34, except that it is applied to the .top face 24 of the casting 22 behind the gear housing 42. Rolls 13-13 are adjusted in a similar man'- ner by a hand wheel 45 and gearing 46, and

are driven from a shaft 47 through similar.

spindles, one of which is partially shown at 1 48, and through gears'within a housing 49.

The gear housing. 49 is seated'against and fixed. to the side face 26 of the casting 22 behind the bracket 34. Inclined rolls 14-14 are mounted in a similar housing supportedupon a similar bracket 50 fixed to the in clined face 28 of the casting- 23. and rolls 15-15 are similarly mounted upon a bracket (not shown) fixed to the inclined face 29 of casting 23. Rolls. 15-15 are driven from a gearing within a housing 53 seated upon the face 28 of the casting 23 behind the bracket 50, and rolls. 14-14 are similarly driven from a shaft 54 through a gear set similarly applied to' the inclined face 29 ofthe casting 23.

Although the several-pairsof rolls may be shaft 51 through similar spindles 52 and thus simultaneously driven at definite speeds,

the relative speeds of the several pairs being determined by the gear ratios established within the gear trains leading to the respective pairs.

In Figure 8ofthe drawings, only the reducing or working rolls 12-12'; 13-13; 14-

-14; and 15-15, together with their mountings and power transmission or driving mechanisms, are visible. It will be understood, however, that the forward casting 22 and the rear; casting 23 are spaced sufiiciently apart longitudinally of the pass line of the mill to accommodate the intermediate set of re-shaping rolls 17-17 or other re-shaping means,

and suitable provision is also made for the mountin of one ormore pairs of the rounding and finishing rolls 1919 beyond the-rolls 1515. Figure 8 being an end elevation, the details in respect of these rolls 1717 and 19-19 are obscured but the arrangement and mounting thereof in the mill will be readily understood by those skilled in the art. The driving of the rolls 1717 and 19-19 may be conveniently accomplished through suitable gearing connected to the single drive shaft 55 or by means of separate variable speed motors.

lVhile in the method and mill herein above specifically described, the two pairs of reduc- 1 ing or working rolls following the re-shaping rolls are disposed at an angle of substantially 45 degrees with respect to the first two pairs of reducing'or working rolls, respectively, it will be readily appreciated that the invention is not limited to this particular angular relationship. In its broader aspects, the invention contemplates the forming of grooves in the interior of the wall of the blank by compressing and reducing peripherally separated portions thereof against a bar and then similarly compressing the intermediate (7 thick portions against the bar to reduce and merge said portions with the previously reduced portions to form a Wall of substantially uniform thickness thropghout. As will be obvious, this may be accomplished with angular relationships other than those specifically. illustrated and described herein and it is not therefore desired to limit or restrict the invention in'this or in any other particular, save as defined in the appended claims.

I claim 1. The improved method of forming seamless tubing which comprises inserting a bar into a tubular blank, passing the blank and bar between two successive pairs of rolls respectively disposed in planes normal to each other, passing the blank and bar between two other successive pairs of rolls respectively dis posed in planes normal to each other and at angles of substantially forty-five degrees with respect o the planes of said first pairs of rolls, an X reshaping the blank after it passes said last named pairs of rolls to free the same from the bar.

' 2. The improved method of forming seamlesstubing which comprises inserting a bar into a tubular blank, passing the blank and bar /between two successive pairs of rolls respeotively disposed in planes normal to each other, passing the bar and blank between two other successive pairs of rolls respectively disposed in planes normal to each other and at angles of substantially forty-five degrees withrespect to the planes of said first named pairs of rolls, reshaping the blank prior to admission thereof to said last named pairs of rolls and reshaping the blank after it passes said last named pairs of rolls to free the same from the bar.

3. In a mill for rolling seamless tubing the combination of four rolls arranged in successive pairs respectively disposed in planes normal to each other, four additional rolls arranged in successive pairs respectively disposed in planes normal to each other and at angles of substantially forty-five degrees with respect to the planes of said first pairs of rolls, all of said rolls being substantially tangential to a common pass line therebetween, grooves in each pair of rolls cooperating to form a blank passage therebetween, and a blank receiving bar movable with a blank through said passages and coacting therewith to reduce the wall thickness of the blank.

4:. In a mill for rolling seamless tubing the combination of four rolls arranged in successive pairs respectively disposed in planes normal to each other, four additional rolls arranged in successive pairs respectively disposed in planes normal to each other and at angles of substantially forty-five degrees with respect to the planes of said first pairs of rolls, all of said rolls being substantially tangential to a common pass line therebetween, grooves in each pair of rolls cooperating to form a blank passage therebetween, a blank receiving bar movable with a blank through said passages to reduce the wall thickness of the blank, and means intermediate said first and last named rolls for reshaping the blank before admission to said last namedrolls.

5. In a mill for rolling seamless tubing the combination of four rolls arrangedin successive pairs respectively disposed in planes normal to each other, four additional rolls arranged in successive pairs respectively disposed in planes normal to each other and at angles of forty-five degrees with respect to the planes of said first pairs of rolls, all of said rolls being substantially tangential to a common pass line therebetween,-coacting grooves in each pair of rolls forming a blank passage therebetween, a blank receiving bar movable with a blank through said passages to reduce the wall thickness of the blank, means intermediate said first and last named rolls for reshaping the blank prior to admission to said last named rolls, and means for blank against said bar to reduce and merge said portions with the previously reduced the wall thick'ness'of said portionswhile causing other portions to stand off from the 0 bar, then reducing the wall thickness of the latter portions by compressing against said bar, and then reducing the wall thickness of the portions of said blank lying intermediate the previously reduced portions bycompressing said intermediate portions against said bar.

8. The improved method of producing seamless tubing from an apertured blank which consists in placing said blank over a bar, compressing peripherally separated portions of said blank against said bar to reduce the wall thickness ofsaid portions, while leaving thick portions or ribs on the interior of said blank intermediate said portions, and then compressing the thick portions or ribs against said bar to cause a reduction and merging thereof with said previously com-- pressed portions to form a wall of substantially uniform thickness throughout. q 9. The improved method of rolling seamless tubing in a continuous mill from an apertured blank which consists in placing said blank over a bar,comprising the blank at a plurality of separated-locations about its periphery against said bar by arolling action to thereby reduce the wall thickness of said blank at such locations while permitting the blank to separate from the bar at intermediate locations, then compressing the blank against said bar at said intermediate locations by a rolling action to thereby reduce the wall thickness of said blank at such locations while permitting the portionsfirst reduced to separate from the bar, and then com pressing the blank against the bar by a rolling action confined to the portions of said blank lying intermediate the areas of greatest reduction resulting from the previous compressions to thereby produce tubing of substantially uniform wall thickness throughout.

10. The improved method of producing seamless tubing in a continuous mill from an apertured blank which consists in placing said blank over a bar of less diameter than the internal diameter of the blank, then compressing and collapsing said blank against said bar by subjecting'it to a reducing pressure on opposite sides thereof and allowing it to separate from the bar at substantially right angles to the 'plane of compression,

then compressing and collapsing said blank against said bar by subjecting 1t to a reducing pressure in a plane normal to that of the first compression and allowing the portions first com ressed to separatefromthe bar, then re-s aping theblank and repeating the aforesaid reducing steps upon those portions of the blank lying intermediate the 7 areas of greatest reduction under the preceding compressions.

'11. The improved method of producing seamless tubing from anapertured blank which consists in compressing peripherally separated portions of the Wall of said blank between pairs of equally spaced substantially parallel surfaces toreduce the thickness of said portions while leaving thick-portions or ribs on the interior of the blank intermediate said reduced portions, and'then compressing the thick portions or ribs between pairs of equally spaced substantially parallel surfaces with the spacings equal to the parallel surface spacings previously employedto cause a reduction and merging of the thick portions or ribs with the previously reduced portions to form a wall of substantially uniform thickness throughout.

12. The improved method of producing seamless tubing from an apertured blank which consists in compressing peripherally separated portions of the wall of said blank between pairs of equally spaced substantially parallel surfaces to uniformly reduce the thickness of said portions while causing other portions of said wall to bulge outwardly, then uniformly reducing the thickness of the latter portions of said wall by compressing between pairsof equally spaced substantially parallel surfaces with the spacings equal to the parallel surface spacings of the first operation and then uniformly reducing the thickness of the portions of said wall lying intermediate the previously reduced portions by compressing said intermediate portions between pairs of equally spaced substantially parallel surfaces with the spacings also equal to the parallel surface spacings of the first operation.

13. The improved method of producing seamless tubing in a continuous mill from an apertured blank which consists in placing said blank over a bar of less diameter than the internal diameter of the blank, then compressing and collapsingsaid blank against said bar by subjecting it to a reducing pressure on opposite sides thereof and allowing it to separate from the bar at susbtantially right angles to the plane of compression,

-then compressing and collapsing said blank through rounding or finishing rolls and free ing the blank from the bar.

14. In a mill for rolling seamless tubing, the combination ofa plurality of grooved rolls arranged about a common pass line, a blank receiving bar for passage with a blank between said rolls, the bases ofthe roll grooves being equally spaced from the bar and each being parallel therewith in a plane passing through its center of rotation and normal to the pass line, certain of said rolls being angularly disposed about the pass linein such wise as to partially imbed said bar into the inner wall of the blank to form grooves and ridges therein, and others of said rolls being angularly displaced with respect to the former in such wiseas to compress and reduce the ridges of said wall against said bar to thereby form a .wall of uniform thickness throughout.

15. The improved method of producing seamless tubing from anvapertured blank, which consists in placing said blank over a bar, reducing the thickness of peripherally separated portions of the wall of said blank between'said bar and rolling surfaces parallel therewith and equidistantly spaced therefrom while causing the excess metal to flow longitudinally of the blank, and then reducing the intermediate portions of said wall between said bar and rolling surfaces parallel therewith and'spaced therefrom to the same extent as the rolls in the preceding reductions and of suificient extent circumferentially of the blank to overlap the adj acent previously reduced portions while causing the excess metal to flow longitudinally of the blank, to thereby elongate the blank and reduce the wall thickness thereof uniformly throughout.

16. The improved method of producing seamlesstubing from an apertured blank, which consists in placing said blank over a bar, reducing to uniform thickness four peripherally separated portions of the wall of said blank between said bar and rolling surfaces equi-distantly spaced therefrom and each parallel therewith throughout an angle in excess ofs45 degrees while causing the excess metal to be displaced longitudinally of the blank, reducing to uniform thickness the intermediate portions of the wall 7 of said blank in the same manner between said bar and rolling surfaces respectively parallel therewith throughout an angle in excess of 45 degrees and spaced therefrom to the same extent as in the first reductions while causing the excess metal to be displaced longitudinally of the blank, to thereby elongate said blank and uniformly reduce the wall thickness thereof throughout.

17. In a mill for rolling seamless tubing, the combination of a plurality of grooved rolls arranged about a common pass line, a blank receiving bar for passage with a blank uniform thickness co-extensive with the angles of paralleIism between the roll grooves and bar, and others of said rolls being angularly'displaced with respect to the former in such wise that the bases of the grooves therein engage the'portions of said wall intermediate said areas and overlie the latter so as to compress and reduce said portions against said bar and merge the same with said areas to form a Wall of substantially uniform thickness throughout.

18. The improved method of producing 5 seamless tubing from an apertured blank WlllCh consists in placing said blank over a bar, forming alternate grooves and ridges in theinterior 0f the wall of said blank by compressing and reducing peripherallyseparated portions thereof against said bar,

- then compressing the ridge portions of said blank against said bar to reduce and merge said portions with the previously reduced portions to form a tube having a wall of substantially uniform thickness throughout, and then passing said tube through a sizing or reducing mil v In witness whereof, I hereunto subscribe my name this 13th day of April, 1928.

PEHR A. FOREN.

CERTIFICATE, OF CORRECTION.

e Patent No. 1,858, 990. May 17, 193% PEHR A. EOREN.

it is hereby certified that error appears in the printed specification of the above numbered patent' requiring. correction as follows: Page 2, line 52, for the word"'traverse" read transverse; page 5, line 33, claim 9, for "comprising" read compressing; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and seaied this 12th day of July, A. D. 1932.

I M. J. Moore, (Seat) f Acting Commissioner of Patents. 

